Hitherto, there has been known an electric power steering device including: two sets of motor windings, which are arranged in a stator of a motor; and two inverter circuits, which are capable of driving the two sets of motor windings independently of each other, and are arranged in a control unit, in which the electric power steering device is configured to control motor winding sets, which are each a set of one of the two sets of motor windings and one of the two inverter circuits, in cooperation with each other, to thereby continue drive of the motor by a normal motor winding set when the other motor winding set has failed.
There is disclosed an electric power steering device configured to increase, when a short-circuit failure has occurred in a switching element included in an inverter circuit of a control unit, output of a normal motor winding set so as to cancel a brake torque that is caused by a failed motor winding set (e.g., refer to Patent Literature 1).